Steel tie plates and “cut” spikes or other types of spikes have been commonly used to fasten railway rails to wooden crossties since the late 1800s. A vital function of the spikes is to transfer lateral forces from the train wheels to the crossties (or ties) as a train runs over the rails. Over time, a deformation zone can be created in a wooden tie, forming cavities from the top surface of the tie partially along two opposite sides of the spike. Once these cavities are formed, as each wheel runs over a rail, in response to the lateral forces, the spike is free to flex back and forth, much like a flagpole in wind. This flexing causes cracks in the spike, typically about one to two inches beneath the top surface of the wooden tie. Eventually, as a result of fatigue, the spike breaks at the flexing point.
Broken spikes are difficult to detect visually even by professional railway track rail inspectors and have resulted in numerous train derailments all over the world, causing death and injuries, as well as extensive property damage and delays in train movements. As rail shipments of cargo increase, these derailments become increasingly unacceptable, especially if the cargo includes hazardous materials.
Additionally, water and foreign materials, such as dirt and sand, can get into the deformation zones causing damage to the ties, the plate and the spike, reducing the useful life of plates, ties and spikes and requiring more frequent replacements of these components. Thus, the overall maintenance costs of the respective rails is increased by the breakage of the spikes.
There have been many attempts to solve the problem of transferring lateral loads into wooden crossties. For example, plates have been made with ridges or other projections on their bottom surface. However, these approaches were not very successful because they resulted in crushed and damaged wood fibers, thereby reducing the useful life of the tie. In addition, the plates settled into the tie over time, requiring the spikes to be re-driven.